Device for detecting the fitting of a child&#39;s seat

ABSTRACT

A device is disclosed for detecting the installation of a child seat, in particular on a vehicle seat, furnished with one fixed part and one movable mechanism, in which the fixed part has a switch element with two switching states and means for forming an actuating field for the switch element, and the movable mechanism is movable, as a result of the installation of a child seat, from a first position to a second position, thereby making a variation in the actuating field attainable, so that the switch element changes its switching state.

[0001] The invention relates to a device for detecting the installationof a child seat in accordance with claim 1.

[0002] In vehicles that are equipped with an air bag on the passengerside or on the floor, the problem arises that whenever a child seat isinstalled there, tripping the air bag can cause injuries to the child inthe child seat. It is therefore desirable for the installation of achild seat on the applicable vehicle seat to be detected automatically.

ADVANTAGES OF THE INVENTION

[0003] According to the invention, a device for detecting theinstallation of a child seat, in particular on a vehicle seat, with onefixed part and one movable mechanism is furnished, in which the fixedpart has a switch element with two switching states and means forforming an actuating field for the switch element, and the movablemechanism is movable as a result of the installation of a child seatfrom a first position to a second position, thus making a variation inthe actuating field attainable, causing the switch element to change itsswitching state.

[0004] The device has the advantage that the switch element can betripped reliably by the movable mechanism, and the movable mechanism isquite simple in design. In particular, field forming means and theswitch element are disposed on the fixed part and can thus be [sic]reliably and in simple way on one another and are not subject to anymotions whatever during operation. By means of the switch element, asignal can be switched that reminds the driver that the child seat hasbeen installed, or sends information to the air bag controller as aresult of which the applicable air bag is deactivated.

[0005] An embodiment in which the field is a magnetic field and theswitch element is a magnetic switch element is especially advantageous.A magnetic field can be generated especially simply by means of apermanent magnet, in other words without supplying any energy whatever.The switching operation is also especially fast and reliable because ofthe use of a magnetic switch.

[0006] For varying the actuating magnetic field, a shielding means, inparticular a sheet of soft iron, can advantageously be provided, whichis located in the first position in a region between the magnetic switchelement and the magnet and in the second position at least partlyoutside that region. In the first position, the shielding meansshort-circuits the actuating magnetic field. Because of itsconductivity, a sheet of soft iron is especially well suited for thispurpose. A shielding means for the actuating magnetic field representsan especially simple, reliable way of actuating the magnetic switch.

[0007] The magnetic switch element can have a so-called Reed switch. Anembodiment by means of a Hall sensor is also conceivable.

[0008] Alternatively, the actuating field can also be an electromagneticfield, of the kind generated by a light source, for instance. The switchelement in that case has a radiation detector, such as a photoelectricelement.

[0009] In order to return the switch to its outset switching positionagain when the child seat is removed, means for restoring the movablemechanism to the first position can be provided.

[0010] In a variant of the invention, the movable mechanism is supportedrotatably about a pivot point on the fixed part, and the shielding meansis secured to the movable mechanism. In this variant, when the childseat is installed, the shielding means is pivoted from the firstposition, in which it shields the actuating magnetic field from themagnetic switch, into the second position, in which it at least partlyuncovers the actuating magnetic field.

[0011] To achieve especially effective shielding, in this variant theshielding means can be deformed on at least one side in such a way thatin the first position, it at least partly embraces one pole of themagnet.

[0012] If one edge of the shielding means is chamfered toward the pivotpoint, then particularly precise switching of the magnetic switch can beachieved.

[0013] It is also advantageous if the fixed part on its underside has adirt removal slot, which is at least partly engaged by the shieldingmeans. Then dirt, which over the course of time gets into the device andcollects on its underside, can be moved out of the device by the movingshielding means.

[0014] The restoring means, in the first variant, can have a torsionspring that is disposed coaxially with the movable mechanism.

[0015] In another variant, the movable mechanism has one rotatable partand one displaceable part, and the rotatable part is supported rotatablyabout a pivot point on the fixed part, and the displaceable part has theshielding means, and the displaceable part is displaceable from thefirst position to the second position by means of a cam that is locatedon the rotatable part. This variant can be made in an especiallyspace-saving form.

[0016] In this variant, the restoring means can have [sic] which acts onthe displaceable part, and/or can have a torsion spring which isdisposed coaxially with the rotatable part and acts on it.

[0017] In both variants, the fixed part can have two housing halves,which are preferably provided with a number of fixation pins andassociated openings for radial fixation of the two housing halvesrelative to one another.

[0018] The two housing halves can also have positive-displacement dogsand associated openings for axially fixing the housing halves relativeto one another.

[0019] According to the invention, the magnetic switch element can bedesigned for switching a signal for an air bag controller. This makes itpossible to attain an automatic shutoff of the air bag controller in theevent that an installed child seat is detected.

[0020] It is especially advantageous if the movable mechanism has alever that is movable by means of a locking device of the child seat. Alocking device of this kind is present in any case in certain childseats, so that those child seats require no modification.

[0021] It is also advantageous if means for securing in the vehicle seaton a crossbar, in particular in accordance with ISO standard 13216-1(“ISOFix”) are provided.

[0022] The invention further includes a vehicle seat that has at leastone of the above-described detecting devices.

DRAWING

[0023] The invention will be described in terms of two exemplaryembodiments and in conjunction with the drawing. Shown in the drawingare:

[0024]FIG. 1, 2, fragmentary views of the first variant;

[0025]FIG. 3, a sectional view of the first variant;

[0026]FIG. 4, the movable mechanism of the first variant;

[0027]FIG. 5, a view from outside and below on the housing of the firstvariant;

[0028]FIG. 6, a sectional view of the second variant;

[0029]FIG. 7, a detail of the housing; and

[0030]FIG. 8, a diagram illustrating the principle of operation.

[0031] The perspective view in FIG. 1A shows the first variant of theinvention with a housing half 12 of the fixed part 1 removed. Themovable mechanism 2, 3, with shielding means 3 and a lever 10, isdisposed in the first housing half 11 and supported rotatably at thepivot point 7 and is located in first position P1. In the first positionP1, the shielding means 3, which is a sheet of soft iron, is located inthe region 9 between magnet 5 and magnetic switch element 8 (FIG. 1B)and thus shields the actuating magnetic field 5, so that the magneticswitch element 8 will not be penetrated by the magnetic field B of themagnet 5. The switching state of the magnetic switch element 8represents the situation that can be referred to as “no child seatinstalled”. A Reed switch is used as the magnetic switch element 8.

[0032] In the perspective view of FIG. 2, the movable mechanism 2, 3 isin its second position P2. Here, the shielding baffle 3 has been pivotedout of the region 9 between the magnet 5 and the magnetic switch element8, specifically counter to the restoring force of the restoring means 4,which here is designed as a torsion spring. The torsion spring 4 isdisposed coaxially to the movable mechanism 2, 3. The maximum deflectionof the lever 10 is limited by means of a stop on the housing half 11.The magnetic field can thus penetrate the magnetic switch element,causing the latter to change its switching state. As a result, anelectrical signal that represents the situation “child seat installed”is switched.

[0033]FIG. 3 shows further details of the detection device in accordancewith the first variant. It shows a sectional view in the position P1 ofFIG. 1, but seen from the back. The housing half 12 is located in thebackground. The shielding baffle 3 is bent over to the rear (into theplane of the drawing) on one face end 31, so that in the position P1 itsurrounds the magnet 5 at one pole 6. As a result, especially effectiveshielding of the magnetic field is achieved. So that the magnetic switchelement, when the shielding baffle 3 pivots out of the way, will switchparticularly precisely, its rear edge 32 is chamfered toward the pivotpoint 7.

[0034] On the underside, between the two housing halves 11, 12, a slot13 is provided, through which dirt that gets into the housing can beremoved. The cleaning effect is enhanced still further by providing thatthe shielding baffle 3 engages this slot 13 with one corner 33 andslides along it in its motion between the two positions P1, P2.

[0035]FIG. 4 shows the movable mechanism 2, 3, 10 of the first variantfrom behind. The side 31 of the shielding baffle has been bent at anangle toward the front.

[0036] In the outside view from below in FIG. 5, the slot 13 is shown.An electrical terminal 40 is also provided, by way of which the magneticswitch element 8 is connected to the air bag controller.

[0037] In the first variant of the invention described above, themovable mechanism 2, 3 is rotated via the lever 10, as a result of whichthe shielding means 3 is pivoted out of the actuating magnetic field.

[0038] In the second variant of the invention shown in FIG. 6, themovable mechanism 2, 3 has one rotatable part 2 and one displaceablepart 3. The rotatable part 2 includes the lever 10 and a cam 21, whichacts on the shielding baffle 3 that is supported on the displaceablepart 3. The rotary motion of the lever 10 is accordingly converted intoa translational motion of the shielding baffle 3. In the position ofrepose, the shielding baffle 3 is forced by the hoop spring 4 into theregion 9 between the magnet 5 and the magnetic switch 8. In addition,here as well a torsion spring is provided as a restoring means 4 for therotatable part 2.

[0039] Upon deflection by the lever 10, the shielding baffle 3 is forceddownward out of the position P1, counter to the spring stress, out ofthe actuating magnetic field into the position P2.

[0040] The cam 21 has a control curve 22, which assures especially fastswitching of the magnetic switch element 8.

[0041] For both variants, the housing is designed such that it can beput together by simply snapping the two housing halves 11, 12 together.To that end, detent means 18, 19 (FIGS. 1-3) are provided. For fixingthe two housing halves 11, 12 radially to one another, a number offixation pins 16 and associated openings 17 are provided. As shown inFIG. 7, the fixation pins 16 each taper slightly conically (by about 3to 5°). For axial fixation of the housing halves 11, 12 relative to oneanother, positive-displacement dogs 15 are provided, which assure atolerance compensation of the two housing halves 11, 12. In terms oftolerances, the detector is designed such that dirt particles largerthan 0.5 mm cannot get into the housing interior from above or from theside.

[0042] The detection device according to the invention can be built intoa vehicle seat. In accordance with ISO standard 13216-1 (“ISOFix”), theseat has a crossbar between the backrest and the seating surface, and apair of fastening clips for a child seat 200 are located on thiscrossbar. The detection device of the invention is likewise secured inpairs to the fastening clips by means of fastening devices 19.

[0043]FIG. 8 summarizes the principle of operation of the detectiondevice of the invention. If the child seat 200 is thrust into thefastening clips by means of a pair of locking devices 210, then thelever 10 of the detection device of the invention is moved into thesecond position P2, and thus the remainder of the movable mechanism 2, 3is moved into that position as well, so that because of the change infield the magnetic switch 8 changes its switching state. As a result, asignal can be switched that provides the air bag controller with theinformation that the air bag tripper should be deactivated. The wiringof the magnetic switch 8 can be embodied as represented in the drawingby the two resistors R1, R2.

[0044] Since the detection device is present in pairs, the detectionoperation can be performed redundantly, which further increases thereliability and hence enhances the safety of the child in the childseat.

[0045] Since the detection device is mounted on the fastening hoop forthe child seat 200, additional precautions at the child seat and vehicleseat can be dispensed with, making the invention especially economicalto realize.

[0046] The variation in the magnetic field is not limited to the case ofshielding. A variation by means of materials with predetermineddifferent magnetic properties is also possible.

[0047] Hall sensors can also be used in the switch elements 8. Otherkinds of actuating fields B include electromagnetic fields, which thenact on corresponding sensors as switch elements 8. An embodiment with alight source functions on the principle of a photoelectric gate.

[0048] The invention is moreover not limited to detecting an installedchild seat. It is also conceivable for the detection device to be usedanywhere that it is important to detect a seat assembly or otherbuilt-in part in particular positions.

1. A device for detecting the installation of a child seat (200), inparticular on a vehicle seat (100), having a fixed part (1, 11, 12) anda movable mechanism (2, 3), in which the fixed part (1, 11, 12) has aswitch element (8) with two switching states and means (5) for formingan actuating field (B) for the switch element (8), and the movablemechanism (2, 3) is movable from a first position (P1) to a secondposition (P2) as a result of the installation of a child seat (200), andby that means a variation in the actuating field (B) is attainable, sothat the switch element (8) changes its switching state.
 2. The deviceof claim 1, in which the field (B) is a magnetic field and the switchelement (8) is a magnetic switch element.
 3. The device of one of theforegoing claims, in which for varying the field (B), a shielding means(3), in particular a sheet of soft iron, is provided, which in the firstposition (P1) is located in a region (9) between the switch element (8)and the forming means (5) and in the second position (P2) is located atleast partly outside the region (9).
 4. The device of one of theforegoing claims, in which the switch element (8) has a Reed switch or aHall sensor.
 5. The device of claim 1, in which the field (B) is anelectromagnetic field, and the switch element (8) has a radiationdetector.
 6. The device of one of the foregoing claims, in which means(4) for restoring the movable mechanism (2, 3) to the first position(P1) are provided.
 7. The device of one of claims 3-6, in which themovable mechanism (2, 3) is supported on the fixed part (1, 11, 12)rotatably about a pivot point (7), and the shielding means (3) issecured to the movable mechanism (2, 3).
 8. The device of one of claims3-7, in which the shielding means (3), on at least one side (31), isshaped such that in the first position (P1), it at least partly embracesone pole (6) of the magnet (5).
 9. The device of one of claims 3-8, inwhich one edge (32) of the shielding means (3) is chamfered toward thepivot point (7).
 10. The device of one of claims 3-9, in which the fixedpart (1, 11, 12), on the underside, has a dirt removal slot (13), theinside of which is at least partly engaged by the shielding means (3).11. The device of one of claims 6-10, in which the restoring means (4)have a torsion spring, which is disposed coaxially with the movablemechanism (2, 3).
 12. The device of one of claims 3-6, in which themovable mechanism (2, 3) has one rotatable part (2) and one displaceablepart (3), and the rotatable part (2) is supported rotatably about apivot point (7) on the fixed part (1, 11, 12), and the displaceable parthas the shielding means (3), and the displaceable part (3) isdisplaceable from the first position (P1) to the second position (P2) bymeans of a cam (21) that is located on the rotatable part (2).
 13. Thedevice of claim 6 or 12, in which the restoring means (4) have a hoopspring, which acts on the displaceable part (3), and/or a torsionspring, which is disposed coaxially with the rotatable part (2) and actson it.
 14. The device of one of the foregoing claims, in which the fixedpart (1, 11, 12) has two housing halves, preferably with a number offixation pins (16) and associated openings (17) for radial fixation ofthe two housing halves (11, 12) relative to one another.
 15. The deviceof the foregoing claim, in which the two housing halves (11, 12) havepositive-displacement dogs for axial tolerance compensation of thehousing halves (11, 12) to one another.
 16. The device of one of theforegoing claims, in which the magnetic switch element (8) is designedfor switching a signal for an air bag controller.
 17. The device of oneof the foregoing claims, in which the movable mechanism (2, 3) ismovable via a lever (10) by means of a locking device (210) of the childseat (200).
 18. The device of one of the foregoing claims, which hasmeans (19) for securing in the vehicle seat (100) on a crossbar (110),in particular in accordance with ISO 13216-1.
 19. A vehicle seat (100)having at least one device of one of the foregoing claims.